co.paralleluniverse.strands.dataflow

Class Var<T>

java.lang.Object

co.paralleluniverse.strands.dataflow.Var<T>

public class Var<T>
extends java.lang.Object

A dataflow variable. Represents a variable whose value can be set multiple times and by multiple strands, and whose changing values can be monitored and propagated.

Field Summary

Fields

Modifier and Type	Field and Description
static FlightRecorder	RECORDER

Constructor Summary

Constructors

Constructor and Description
Var() Creates a new Var with no history.
Var(FiberScheduler scheduler, SuspendableCallable<T> f) Creates a new Var with no history, whose value is set to the value returned by the given function f; the function will be re-applied, and the Var's value re-set, whenever any of the Vars referenced by f change value.
Var(int history) Creates a new Var.
Var(int history, FiberScheduler scheduler, SuspendableCallable<T> f) Creates a new Var, whose value is set to the value returned by the given function f; the function will be re-applied, and the Var's value re-set, whenever any of the Vars referenced by f change value.
Var(int history, SuspendableCallable<T> f) Creates a new Var, whose value is set to the value returned by the given function f; the function will be re-applied, and the Var's value re-set, whenever any of the Vars referenced by f change value.
Var(SuspendableCallable<T> f) Creates a new Var with no history, whose value is set to the value returned by the given function f; the function will be re-applied, and the Var's value re-set, whenever any of the Vars referenced by f change value.

Method Summary

Modifier and Type	Method and Description
T	get() Returns the Var's current value (more precisely: it returns the oldest value in the maintained history that has not yet been returned), unless this Var does not yet have a value; only in that case will this method block.
T	getNext() Blocks until a new value has been set and returns it.
void	set(T val) Sets a new value for this Var.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

RECORDER

public static final FlightRecorder RECORDER

Constructor Detail

Var

public Var(int history,
           FiberScheduler scheduler,
           SuspendableCallable<T> f)

Creates a new Var, whose value is set to the value returned by the given function f; the function will be re-applied, and the Var's value re-set, whenever any of the Vars referenced by f change value.

Parameters:

history - how many historical values to maintain for each strand reading the var.

scheduler - the FiberScheduler to use to schedule the fiber that will run, and re-run f.

f - this var's value is set to the return value of f

See Also:

get()

Var

public Var(int history,
           SuspendableCallable<T> f)

Creates a new Var, whose value is set to the value returned by the given function f; the function will be re-applied, and the Var's value re-set, whenever any of the Vars referenced by f change value. The fiber running f will be scheduled by the default fiber scheduler.

Parameters:

history - how many historical values to maintain for each strand reading the var.

f - this var's value is set to the return value of f

See Also:

get()

Var

public Var(SuspendableCallable<T> f)

Creates a new Var with no history, whose value is set to the value returned by the given function f; the function will be re-applied, and the Var's value re-set, whenever any of the Vars referenced by f change value. The fiber running f will be scheduled by the default fiber scheduler.

Parameters:

history - how many historical values to maintain for each strand reading the var.

scheduler - the FiberScheduler to use to schedule the fiber that will run, and re-run f.

f - this var's value is set to the return value of f

See Also:

get()

Var

public Var(FiberScheduler scheduler,
           SuspendableCallable<T> f)

Creates a new Var with no history, whose value is set to the value returned by the given function f; the function will be re-applied, and the Var's value re-set, whenever any of the Vars referenced by f change value.

Parameters:

scheduler - the FiberScheduler to use to schedule the fiber that will run, and re-run f.

f - this var's value is set to the return value of f

See Also:

get()

Var

public Var(int history)

Creates a new Var.

Parameters:

history - how many historical values to maintain for each strand reading the var.

See Also:

get()

Var

public Var()

Creates a new Var with no history.

Method Detail

set

public void set(T val)

Sets a new value for this Var. The Var can be set multiple times and by multiple strands.

Parameters:

val - the new value.

get

public T get()
      throws SuspendExecution,
             java.lang.InterruptedException

Returns the Var's current value (more precisely: it returns the oldest value in the maintained history that has not yet been returned), unless this Var does not yet have a value; only in that case will this method block.

Throws:

SuspendExecution

java.lang.InterruptedException

getNext

public T getNext()
          throws SuspendExecution,
                 java.lang.InterruptedException

Blocks until a new value has been set and returns it.

Throws:

SuspendExecution

java.lang.InterruptedException